fbi and dea agents have joined the search for clues in an attack that put a prominent new hampshire doctor and his wife in the hospital. and john schriffen is in bedford, new hampshire, with the latest. good morning, john. >> reporter: george, good morning. as you can see behind me, the driveway to this home is blocked off, because this is still a very active crime scene. while police suggest they do have some leads, they say at this point, none are specific enough to be helpful. crime scene units comb through this million-dollar mansion throughout the night, looking for any evidence of who could have brutally assaulted dr. eduardo casada and his wife, before leaving them for dead. >> the homeowners were confronted by a person or persons of interest. >> reporter: this morning, agents from the fbi and dea have joined the investigation. as dr. casada, a respected anesthesiologist, clings to life at the hospital where he normally works. police say the couple was viciously attacked saturday night, after an apparent home invasion. his wife, sonia, was able to escape, covered in blood. she knock